Position detection device

Abstract

A position detection device applicable to robots and other equipment used in automated assembly line manufacturing processes is disclosed. The device of the present invention provides a position detection device having a simplified construction which can rapidly and accurately establish the orientation and location of workpieces within a work space, and which is suitable for workpieces having at least two straight line edges which are not parallel with respect to one another. The device of the present invention includes first position detection means for optically, or by means of direct contact with the workpiece, mechanically detecting the point of intersection of a line containing a first straight edge among the straight edges of the workpiece and a first detection plane defined within the work space; second position detection means for similarly detecting the point of intersection of a line containing a second straight edge among the straight edges of the workpiece which is different from the first straight edge and a second and third detection plane defined within the work space; storage means for storing data representing the geometric relationship between the first straight edge and second straight edge of the workpiece; and computational means for calculating the position and orientation of the workpiece based on the data stored in the storage means and on the coordinates of the points of intersection detected by the first position detection means and second position detection means.

What is claimed is: 
     
       1. A position detection device for detecting the position in a work space of an object having at least two non-parallel straight edges comprising: a) first position detection means for detecting a point of intersection of a line containing a first straight edge of the workpiece and a first detection plane defined within the work space;   b) second position detection means for detecting the point of intersection of a line containing a second straight edge of the workpiece which is different from said first straight edge and a second and a third detection plane defined within said work space;   c) first storage means for storing first coordinates representing the geometric relationship between said first straight edge and said second straight edge,   d) second storage means for storing second coordinates of said first, second, and third detection planes; and   e) computational means for calculating the three dimensional position and orientation of said workpiece based on the first coordinates stored in said first storage means, the second coordinates stored in said second storage means and the coordinates of the points of intersection detected by said first position detection means and said second position detection means.   
     
     
       2. A position detection device in accordance with claim 1 above, wherein position detection is carried out such that there is no physical contact with said object. 
     
     
       3. A position detection device in accordance with claim 1 above, wherein said first position detection means further comprises: i) first line marker means for projecting a linear first mark on a first surface of said workpiece;   ii) first image capturing means for capturing an image of said first mark projected on said workpiece, said first image capturing means having an optical axis, said image capturing means positioned such that the optical axis of said first image capturing means forms an oblique angle with an optical axis of said first line marker means; and   iii) first image processing means for processing an image captured by said first image capturing means, thereby determining coordinates of a first predetermined point on said work piece.     
     
     
       4. A position detection device in accordance with claim 1 above, wherein said second position detection means further comprises: i) second and third line marker means for projecting a linear second and third mark on a second surface of said workpiece which is different from said first surface;   ii) second and third image capturing means for capturing an image of said second and third marks, respectively, projected on said workpiece, said second and third image capturing means each having an optical axis, said second and third image capturing means each positioned such that the optical axis of said second and third image capturing means forms an oblique angle with an optical axis of said second and third line marker means, respectively; and   iii) second and third image processing means for processing an image captured by said second and third image capturing means, respectively, thereby determining coordinates of a second and third predetermined point on said work piece.     
     
     
       5. A position detection device in accordance with claim 1 a) wherein said first position detection means further comprises: i) first line marker means for projecting a linear first mark on a first surface of said workpiece;   ii) first image capturing means for capturing an image of said first mark projected on said workpiece, said first image capturing means having an optical axis, said image capturing means positioned such that the optical axis of said first image capturing means forms an oblique angle with an optical axis of said first line marker means; and   iii) first image processing means for processing an image captured by said first image capturing means, thereby determining coordinates of a first predetermined point on said work piece;     b) and wherein said second position detection means further comprises: i) second and third line marker means for projecting a linear second and third mark on a second surface of said workpiece which is different from said first surface;   ii) second and third image capturing means for capturing an image of said second and third marks, respectively, projected on said workpiece, said second and third image capturing means each having an optical axis, said second and third image capturing means each positioned such that the optical axis of said second and third image capturing means forms an oblique angle with an optical axis of said second and third line marker means, respectively; and   iii) second and third image processing means for processing an image captured by said second and third image capturing means, respectively, thereby determining coordinates of a second and third predetermined point on said work piece.     
     
     
       6. A position detection device in accordance with claim 5 above, wherein at least one of said first, second and third line marker means includes a laser light source. 
     
     
       7. A position detection device in accordance with claim 1 above, wherein position detection is carried out through physical contact with said object. 
     
     
       8. A position detection device in accordance with claim 1 above, wherein said first position detection means further comprises: i) first tactile sensor for contacting said workpiece at a first point on a first surface of said workpiece;   ii) first tactile data generating means for generating tactile data based on a position of said first tactile sensor when said first tactile sensor makes contact with said workpiece at said first point; and   iii) first tactile data processing means for processing tactile data generated by said first tactile data generating means, thereby determining coordinates of a first predetermined point on said workpiece.     
     
     
       9. A position detection device in accordance with claim 1 above, wherein said second position detection means further comprises: i) second and third tactile sensors for contacting said workpiece at a second and third point on a second surface of said workpiece which is different from said first surface;   ii) second and third tactile data generating means for generating tactile data based on a position of said second and third tactile sensors when said second and third tactile sensors makes contact with said workpiece at said second and third points, respectively; and   iii) second and third tactile data processing means for processing tactile data generated by said second and third tactile data processing means, respectively, thereby determining coordinates of a second and third predetermined point on said workpiece.     
     
     
       10. A position detection device in accordance with claim 1 above, a) wherein said first position detection means further comprises: i) first tactile sensor for contacting said workpiece at a first point on a first surface of said workpiece;   ii) first tactile data generating means for generating tactile data based on a position of said first tactile sensor when said first tactile sensor makes contact with said workpiece at said first point; and   iii) first tactile data processing means for processing tactile data generated by said first tactile data generating means, thereby determining coordinates of a first predetermined point on said workpiece;     b) and wherein said second position detection means further comprises: i) second and third tactile sensors for contacting said workpiece at a second and third point on a second surface of said workpiece which is different from said first surface;   ii) second and third tactile data generating means for generating tactile data based on a position of said second and third tactile sensors when said second and third tactile sensors makes contact with said workpiece at said second and third points, respectively; and   iii) second and third tactile data processing means for processing tactile data generated by said second and third tactile data processing means, respectively, thereby determining coordinates of a second and third predetermined point on said workpiece.     
     
     
       11. A position detection device in accordance with claim 10 above, wherein at least one of said first, second and third tactile data generating means consists of a potentiometer which outputs electric output signals proportional to mechanical movement of said workpiece. 
     
     
       12. A position detection device in accordance with claim 1, wherein said first storage means stores data representing a distance and an angle between said first straight edge and said second straight edge.